The University of Washington Center for Studies in Demography and Ecology requests a continuation of the Population Research Infrastructure Award first received in 2002. For many years, CSDE has been the intellectual center of a diverse group of population scientists at UW. After a period of dramatic growth made possible by our initial funding from NICHD and strong institutional support, CSDE now supports a cohesive research community of 55 researchers at UW (including sociologists, economists, psychologists, geographers, anthropologists, and statisticians) anchored by a weekly seminar series, collaborative projects, and access to state-of-the-art technical and administrative services. CSDE researchers also include 20 regional affiliates from Western Washington University, the University of Victoria, and Battelle Institute. CSDE's research portfolio is notably broad and innovative, with projects contributing to five signature themes: Family Demography;Migrants, Minorities, and Unequal Opportunities;Social and Biological Contexts of Population Health;Population-Environment Dynamics;and Demographic Methods. The advancement of these themes towards a greater integration of demography with biological and environmental science has been fostered by CSDE scholars'extensive institutional and intellectual links beyond the social sciences, including UW's renowned biomedical and natural science programs. The proposed infrastructure award will support the services provided by the successful Adminstrative, Computing, Statistics, Information, and Biodemography Cores, as well as a new Developmental Infrastructure Core designed to support pilot work that can lead to extramurally-funded research, assist the career development of new population scientists and encourage interdisciplinary collaborative projects that explore new research directions. A major expansion of the Statistics Core will provide expertise in spatial analysis to a wide range of projects with rich spatial data. The research infrastructure services provided by CSDE have increased the quality and breadth of research in population and public health at UW and in the Northwest, and have cultivated the next generation of researchers. Proposed new initiatives will further enhance the research environment and the capabilities of CSDE researchers.